Allen 56601G 13-Key SAE Magnetic Ball-Plus Hex Key Set From Allen, the original manufacturer of the hex key Ball-Plus hex keys permit an entry angle up to 25-Degree to work in hard-to-reach areas Magnetic head provides efficiency in holding fasteners in tight work areas Heat treated, tempered alloy steel provides high strength and resistance to rotational distortion All hex keys are precision formed to exact dimensional tolerances for precise fit